Motl was partner in the law firm of Reynolds, Motl & Sherwood in Helena, Montana from 1982 through 2013. In 2013, he was appointed to the role of Montana Commissioner of Political Practices. He is a member of the State Bar of Montana, Montana Trial Lawyers Association, and the Association of Trial Lawyers of America. He serves on the boards of the Montana Justice Foundation and the Montana Public Interest Research Foundation. In 1979-1981, he was a staff aide to Ralph Nader.